Millions of syringes, such as that depicted in FIG. 1 (2), are consumed in healthcare environments every day. A typical syringe (2) comprises a tubular body (4), a plunger (6), and an injection needle (8). Typical syringes are supplied empty and may be filled from a medicine vial at the point of use. FIG. 2 illustrates the process of filling a syringe (2) with a needle (8) from a vial of liquid injectable medicine (10). The medicine can be liquid or a powder mixed with a liquid at the time of use. FIG. 3 shows the needle (8) which is used with traditional syringes (12). The needle is connected to the syringe with a needle hub (19), and a luer lock adapter (14) on the front of the syringe.
The use of needle injection configurations, carries with it the risk of a sharp needle contacting or poking a structure that is not desired. For this reason, socalled “safety syringes” have been developed. One safety syringe (20) configuration is shown in FIG. 4, wherein a tubular shield member (22) is spring biased to cover the needle (8) when released from a locked position relative to the syringe body (4).
Such a configuration may be perceived suboptimally by users as bulky and cumbersome to use. For example, the external spring based shield is relatively large, and may rapidly activate, thereby spraying blood particles in unwanted directions, such as on the user. In some instances it is desirable to pre-fill the syringe with drug at the factory to eliminate the filling step shown in FIG. 2. Further, existing safety syringe configurations generally are not compatible with being pre-filled with drug. Common drugs for injection may be in liquid form, or may comprise a powder mixed with a liquid at the time of use. The elastomer and polymer materials of such a system can leech materials, moisture, or oxygen into liquid contained within the syringe body over time. Pre-filled glass syringe bodies are shown in FIG. 5. The pre-filled syringe is constructed of a glass tubular body (4) with a plunger (6) attached to a stopper (5) and either a permanently coupled needle (8) or a luer lock connection (14) for connection of a needle at the point of use. The glass body is used to minimize any leeching of contaminants, moisture, or oxygen into the drug. These glass syringe bodies generally are not compatible with current safety syringe systems. There is a need for improved injection systems which address the shortcomings of currently-available configurations.